Wren Yang

Wren is Robin's younger brother. He speaks in a mannerism of old English at times, once referring to Ethan as Robin's 'beau'. He gets annoyed very easily.

Personality
Wren seems to be rather blunt. He's eccentric and snarky.

Robin
Robin is his older sister, who he treats snarkily in his first introduction. She appears to be used to this treatment from him.

Ethan
His first impression of Ethan is that of a peppy, overly-friendly dog. He expresses distaste before letting him into the Yang residence, and sending him upstairs without introducing himself to Ethan.

Miu
Miu is his mother, who of which scolds him heavily for letting a stranger into the home without notice.

Trivia

 * Wren can speak both English and Japanese.